Clarence Erwin McClung (April 5, 1870 - January 17, 1946) was an eminent American zoologist and prairie pioneer cytologist who discovered the role of chromosomes in sex-determination. (wikipedia.org)
Studies by University of Kansas zoologist Clarence Erwin McClung in Lawrence, Kansas at the turn of the twentieth century helped researchers focus on the roles of chromosomes for sex determination. (asu.edu)
She realized that the previous idea of Clarence Erwin McClung, that the X chromosome determines sex, was wrong and that sex determination is, in fact, due to the presence or absence of the Y chromosome. (iiab.me)
This collection centers around Dr. Wenrich's efforts to honor Dr. Clarence Erwin McClung. (upenn.edu)
Famous for his work in sex discrimination and chromosomes, McClung was the managing editor of the Journal of Morphology for more than twenty years. (upenn.edu)
McClung, Charles Erwin, 1870-1946 - General subdivision-Biography. (upenn.edu)
The Y chromosome was identified as a sex-determining chromosome by Nettie Stevens at Bryn Mawr College in 1905 during a study of the mealworm Tenebrio molitor . (iiab.me)
The Sry gene, located on the short branch of the Y chromosome, initiates male embryonic development in the XY sex determination system. (asu.edu)
That research showed that mutations in the Sry gene halted the embryonic development of testes, resulting in organisms that possessed a Y chromosome but expressed female phenotypic characteristics. (asu.edu)
In mammals, the Y chromosome contains a gene, SRY , which triggers embryonic development as a male. (iiab.me)
Zoologist1
Her results supported the theory proposed in the early 1890s by zoologist researcher Walter Sutton at Columbia University in New York City, New York and biologist Theodore Boveri at University of Würzburg in Würzburg, Germany, that chromosomes contain genetic material. (asu.edu)
19052
Nettie Maria Stevens, a post-doctorate researcher at Bryn Mawr College, located near Philadelphia, Pennsylvania, expanded upon McClung's theory in 1905, observing that spermatozoa are of two distinct forms, containing either an X or a Y chromosome. (asu.edu)
In 1905, soon after the rediscovery of Mendel's paper on genetics in 1900, she observed that male mealworms produced two kinds of sperm, one with a large chromosome and one with a small chromosome. (geneastar.org)
Sexes1
After receiving the grant, she used germ cells of aphids to examine possible differences in chromosome sets between the two sexes. (geneastar.org)
Mammals7
The Sex-determining Region Y ( Sry in mammals but SRY in humans) is a gene found on Y chromosomes that leads to the development of male phenotypes, such as testes. (asu.edu)
Scientists first scanned the Y chromosomes of several mammals for the presence of genes involved in testis formation. (asu.edu)
The team found a sequence on the Y chromosomes of several species of mammals. (asu.edu)
The Y chromosome is one of two sex chromosomes ( allosomes ) in mammals, including humans , and many other animals. (iiab.me)
In mammals, the Y chromosome contains the gene SRY , which by default triggers male development. (iiab.me)
The Y chromosomes of humans and other mammals also contain other genes needed for normal sperm production. (iiab.me)
[18] This re-estimation of the age of the therian XY system is based on the finding that sequences that are on the X chromosomes of marsupials and eutherian mammals are present on the autosomes of platypus and birds. (iiab.me)
Genes3
Starting in the early 1980s, research teams in London, UK led by Robin Lovell-Badge at the National Institute for Medical Research and Peter Goodfellow at the Cancer Research UK London Research Institute sought to identify the genes present on the Y chromosome that induced male development. (asu.edu)
[7] All Y-linked genes are expressed and (apart from duplicated genes) hemizygous (present on only one chromosome) except in the cases of aneuploidy such as XYY syndrome or XXYY syndrome . (iiab.me)
Over time, genes that were beneficial for males and harmful to (or had no effect on) females either developed on the Y chromosome or were acquired through the process of translocation . (iiab.me)
Humans2
In humans the first step in the development of an organism's sex is the inheritance of an X chromosome from the mother, and either an X or Y chromosome from the father. (asu.edu)
With a 30% difference between humans and chimpanzees, the Y chromosome is one of the fastest-evolving parts of the human genome . (iiab.me)
Species3
Based upon her research on sex determination in insect species, Stevens concluded that the Y chromosome carries the genetic material that leads to male development. (asu.edu)
Y is normally the sex-determining chromosome in many species, since it is the presence or absence of Y that typically determines the male or female sex of offspring produced in sexual reproduction . (iiab.me)
During his career Dr. Wenrich named three new genera and twelve new species of protozoa, wrote more than one hundred and ten articles and chapters of books on chromosomes in insects, on protozoa and related subjects, and was elected to twenty-five honorary and professional societies. (upenn.edu)
Determination1
Stevens's work identified the Y chromosome as a heritable structure that somehow caused sex determination in the embryo. (asu.edu)
Work2
At that time, however, researchers couldn't detail the mechanism through which chromosomes work to induce changes in the cell. (asu.edu)
In her pioneering work at Bryn Mawr College, Stevens - whose birthday is today, July 2 - discovered the sex chromosomes that make the difference. (geniuses.club)
Father1
[5] The Y chromosome is passed only from father to son. (iiab.me)
Female1
When the sperm with the large chromosome fertilized eggs, they produced female offspring, and when the sperm with the small chromosome fertilized eggs, they produced male offspring. (geneastar.org)
It is entirely coincidental that the Y chromosome, during mitosis, has two very short branches which can look merged under the microscope and appear as the descender of a Y-shape. (iiab.me)